Heart chapter biology Flashcards
What is translocation
a movement of organic solvent from leaves where photosynthesis occurs to sieve tube to be carried to sink.example fruit,storage of bulb
Explain the mass flow hypothesis
-where it occurs
-what is transported
-what happens at source point/whats produced
-where is it loaded into…against concentration gradient via
-so how is the water potential in sieve tube
–what the nearby xylem does
- what pressure is caused
-what happen at sink
for …..to be coverted to starch
-what happens at cell at sink
-what does water does
-what happens to the hydostatic pressure
-what is between the source and sink
name 4 major vessels
-aorta(artery)
-inferioer vena cava(down)(vein)
-superior vena cava(up)Vein)
-pulomanry artery
pulmonary vein
diffreantiate vein and artery
-size of lumen
-thickness of wall
-carrying blood
-presence of valve
-pressure of blood
explain about cardiac cycle
-what is hear-t
-what the muscle does
-what is cardiac cycle
-what is the normal heartbeat of a human
-how long is one complete cardiac cycle
-explain about atrial systole,ventricular systole,cardiac diastole
Atrial diastole
Pressure in the atria is low; [1 mark]
-blood enters the two atria fro vena cava and pulmonary vein(deoxygenated blood enters the right atrium and oxygenated
blood enters the left atrium).
Atrial systole
The wave of excitation that begins at the sinoatrial node (SAN) spreads to both atria. Both atria contract simultaneously. [1 mark]
-Pressure in the atria increases, [1 mark]
-blood is forced into the ventricles via the tricuspid valves and bicuspid valves (the atrio- ventricular valves) which are open. [1 mark]
ventricular systole
The atrio-ventricular node (AVN) is stimulated. [1 mark] -The wave of excitation is conducted along the bundle of His and its branches the Purkinje,
-Both ventricles contract, pressure increases, closing the tricuspid valves and bicuspid valves and causes the first heart sound, ‘lub’. [1 mark]
-The pressure forces open the semi-lunar valves of the aorta and pulmonary artery and blood is forced into these vessels.
ventricular diastole
Ventricles are relaxed. [1 mark]
The closing of the semilunar valves at the base of the aorta and pulmonary artery causes the second heart sound, ‘dub’. [1 mark]
Blood in the vena cava and pulmonary veins flow into the right atrium and left atrium espectively. [1 mark]
Importance of blood circulation
-transport oxygenated blood from lungs to tissue
-transport excretory waste products fro tissue to excretory organ
-transport co2 from cell to lungs
-transport blood clotting factor to reduce blood loss in case of injuries
-transport hormones from endocrine organ to target cell
-distribute heat in the body to maintain body temprature
describe how a diet in high colestrol increase risk of cardiovascular disease
what happens to the endothelium of coronary artery?
what is causes?
what does saturated and cholesterol does?
what happens to the cell in stratum intima,stimulated by what fats?
what happens to atrial wall?
what causes artheroclerosis?
what happens to the lumen of the coronary artery ?
what does calcium ion do?
the lumen can be complety blocked causing?
describe the movement of fluid between blood and intersitial fluid?
explain the regulation of hearbeat
The heartbeat is regulated by the following mechanisms;
P6 Impulse from the cardiac inhibitory centre in the medulla is transmitted to the sinoatrial node through the parasympathetic nerve to reduce the rate of heartbeat.
P7 Impulse from the cardiac acceleratory centre in the medulla is transmitted to the sinoatrial node through the sympathetic nerve to increase the rate of heartbeat.
P8 Adrenaline hormone secreted by adrenal glands increases the rate of heartbeat. P9 Thyroxine hormone secreted by thyroid glands increases the rate of heartbeat.
explain the structure of a heart and the adaptations to function as blood pumping organ
P1 A heart comprises of four chambers: right and left atria (auricles) and right and left
Ventricles. E1 The outer walls of auricle are thinner than the outer walls of ventricles to generate from auricle into ventricle.//
lower pressure needed to pump blood E1 The left ventricle wall is thicker than the right ventricle wall to generate more pressure
needed to pump the blood to the entire body. //
E1 The right ventricle generates lower pressure since it pumps blood to the lungs.
P2 The septum, which separates the right and left parts of heart, E2 also prevents the mixture of oxygenated blood on the left with deoxygenated blood on
the right. P3+ E3 Deoxygenated blood enters the right atrium through the vena cava, while enters the left atrium through the pulmonary vein.
oxygenated blood from the lungs P4+E4 Deoxygenated blood from the right atrium is pumped into the right ventricle, while
oxygenated blood from the left atrium is pumped into the left ventricle.
> Thivyasri Krishnan:
P5 +E5 The deoxygenated blood from the right ventricle flows to the lungs through pulmonary artery, P6+E6 while the oxygenated blood from the left ventricle is pumped to the body tissue
through aorta. P7 The tricuspid valve between the right atrium and right ventricle, and the bicuspid
between the left atrium and left ventricle E7 prevents the blood in the ventricles from flowing back into the atriums.
P8 The bicuspid and tricuspid valves are prevented from inverting
E8 by the fibrous tissues cord called chordae tendineae.
P9 Semilunar valves at the base of pulmonary artery and aorta
E9 prevents blood from flowing back into the respective ventricles.
P10 Cardiac muscles of the heart are branched and connected to one another by intercalated disks and cross bridges
E10 to facilitate the spread of contractile wave
